Water-tube boiler.



No. 716,875. Patented Dec. 30, |902.

T. DUNLAP." WAER TUBE BUILER.

(Application filed :une 19, :vom (No Modem lllllllll wsTNEss'n-s.- ENToR:

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UNITED STATES PATENT OEETCE.

THOMASv DUNLAP, OF TOLEDO, OHIO.

WATER-TUBE BOILER.

.SPECIFICATION forming part of vLetters Patent No. 716,875, dated `:December 30, 1902.

To a/ZZ whom, it ino/y corwcrrt:

Be it known that I, THoMAs DUNLAP, a citizen of the United States, residing at Toledo, in the count-y of Lucas and State of Ohio,have invented certain new and `useful Improvements in Water-Tube Boilers; and I do declare the following to be a full, clear,and exact description of the invention, such as will enable others skilled in the art to which itappertains to make and use the same, reference beingr had to the accompanying drawings, and to the figures of reference marked thereon, which form a part of this specification.

One of the most serious difticulties encountered in the use of water-tube boilers is the formation of crust and scale upon the watersurfaces of the tubes, especially those tubes which are exposed to the more intense heat of the furnace. The ineiliciency and rapid deterioration and final destruction of an in'- crusted tube are Well understood. Experience has shown that for some reason new boiler-tubes will for a long timeresist the action of scale-forming matter and will remain clean, while an old tube which has once become incrusted with scale will, no matter how thoroughly it may be cleaned, again quickly become incrusted, thus demonstrating that the scale-forming matter in the water has a much greater adinity for an incrusted or partially-incrusted surface than for a clean surface. Y

My invention is designed to take advantage of the fact here stated and to protect the tubes of boilers from incrustationl by supporting within the tube and out of contact therewith a body of some material or substance which has an aflinity for scalefor1ningmatter such, for instance, as a bar or tube of iron which has been previously coated or iucrusted with scale-forming matter.` -These bars or tubes are designed to be readily removable, so that they may be cleansed and returned quickly and with little labor.

My invention also relates to certain details of boiler construction hereinafter pointed out.

I attain the objects above referred to by means of the devices and arrangement of parts hereinafter described, and shown and illustrated in the accompanying drawings, in which- Figure l is a side elevation of a boiler em- Applioation tiled June 19, liBOl. Serial No. 65,091. (No model.)

bodyiug my invention, one half being in central vertical section on line at', Fig. 2; Fig. 2, a top plan view of the same with the cover removed, one half being in horizontal section on line .fc Fig. 1; Fig. 3, a top plan view of one of the tubes hereinafter referred to,show ing a means for supporting the'scale-accumulator hereinafter referred to; and Figa is a side elevation, in central vertical section, of the same.

Like numerals of reference indicate like parts throughout the drawings.

In the drawings, l is the cylindrical shell oi a vertical boiler. Within the shell are three horizontal partitions or flue-sheets 2, 3, and 4, secured at their margins to the inner wall of the shell.

5 5 are lire-chambers of cylindrical form, the tops of which are formed by the top fluesheet 2, the bottoms being formed by the middie flue-sheet 3. These tire-boxes may be of any desired number, according to the transverse area of the boiler. In the example illustrated in the drawings four fire-boxes are shown arrangedat equidistant intervals and as large as the interior'of the shell will admit. Into each of the iire-boxes near its top leads a pipe 6, designed for the admission of a liquid or gaseous fuel. Each of these pipes is provided with asuitable valve (not shown in the drawings) for controlling the dow of fuel. From the bottom of each ot the fire-boxes leads a central down-pipe 7 through the bottom flue-sheet 4:. The products of combustion from the'v fire-boxes pass downwardly through the Atubes 7 into the chamber 8 beneath the flue-sheet 4, thence out through conduit 9 to the smoke-staek/or chimney. Y

Passing through each of tirelire-boxes vertically and communicating with the chamber above the flue-sheet 2 and with the chamber between the due-sheets 3 and 4: is a series of water-tubes lO. These tubes are arranged in a circle near the wall of each of the tire-boxes and on their exterior areexpo'sed to the direct action of the fires. In the upper and the middle flue-sheet are large openings ll to facilitate the circulation of water between the lower water-chamber, the upper steam and water chamber, and around the lire-boxes.

My boiler is provided with a feed-Water pipe IOO 12, blow-off pipe 13, and steam-pipe 14, together with the usual valves and appliances commonly found in steam-boilers.

In each of the water-tubes is supported a body of metal 15, which for illustration I have shown as a bar of iron formed in transverse section as a cross. This piece may, however, be cylindrical, tubular, or of any other desired formin cross-section. This baris suspended from a bridge or spider 16, which bestrides the upper opening of the tube, the bar having a threaded bolt 17, which projects through an opening in the bridge or spider. The bolt atits upperend is provided with a nut 1S. At bottom the bar 15 is split and flared outwardly, so that a mere knife-edge contacts with the bottom flange of the tube, thus holding the bar in vertical position and preventing its coming in cont-act with the interior of,its tube. Each of these bars before it is placed in position is incrusted with scale, which may be accomplished in a variety of ways-as, for instance, by depositing the bars in the hottest part of a boiler in which water strong in scale-forming matter is used. After a time scale will be deposited upon the bars, and the bars will then be it for use in preventingincrustatiou upon new tubes.

My boiler is provided with a top or cover 1, the shell and the cover being connected by bolts 1b, engaging meeting anges on the two parts. When the bolts and nuts are removed,

the top may by suitable hoisting devices be removed. Now each one of the vertical tubes will be exposed, and the bars are readily accessible for inspection, cleaning, and repairs. It will be seen that each one of the pieces may be quickly removed and that with two interchangeable sets of scale-collectors the boiler need not at any time be long out of service.

It will be seen that the boiler here shown is of compact form, affording large heatingsurfaces and extensive steam-liberating area, that the tubes and ire-boxes are readily accessible for cleaning and repairs, and that the incrustation of the tubes is reduced to a minimum. My boiler may be used singly or in battery.

Having described my invention, what I claim, and desire to secure by Letters Patent,

In a steam-boiler, a Water-tube, a bar of metal which has been independently incrusted with scale, and means for removably supporting said bar Within the tube and without contact Within the interior surface thereof.

In testimony whereof I affix my signature in presence of two witnesses.

THOMAS DUNLAP.

Witnesses:

F. M. DoTsoN, L. E. BROWN. 

